1. Field of the Invention
This disclosure relates generally to smoke alarms and wireless telecommunications systems. More specifically, this disclosure provides a combination device and method for locating a smoke alarm utilizing wireless E-911 telecommunication location systems.
2. Description of Related Art
Smoke Alarm Devices and Systems
Smoke alarm devices and systems are valuable fire protection tools that save life and property. Detecting smoke at the earliest stages of a fire, alerting building occupants for rapid, evacuation, and notifying emergency response resources of the fire are key factors for any general fire safety plan. However, failure of any one of the key factors increases the fire danger. Preparing for fire scenarios, reducing physical injury, reducing loss of life, and reducing property damage are all dependent upon building occupants safely evacuating a burning building and quickly contacting emergency response personnel.
One type of smoke alarm device is a self-contained, independent smoke alarm unit with photoelectric, ionization, or both types of sensors to detect smoke, provide an AC and/or DC power source, and provide an audible alarm horn and/or visual alarm signal to alert building occupants of a potential fire. For example, a FIRST ALERT® SA302 smoke alarm provides both photoelectric and ionization sensors in one unit. A GENTEX® DL2220 smoke alarm features an ADA-compliant 90 dB audible alarm horn and 177 candela strobe light for hearing impaired persons.
One drawback of such self-contained units is that these units do not communicate with each other. For instance, in larger buildings containing many rooms or multiple levels, even when equipped with multiple self-contained smoke alarm units, the self-contained smoke alarm may detect smoke and fire in remote or unoccupied areas for unknown periods of time before the occupants are alerted to the fire, which allows the fire to spread. Furthermore, physically-challenged, intoxicated, or sleeping occupants may not hear or otherwise respond to the audible or visual alarm of the self-contained unit located in a remote part of the building before being overcome by smoke inhalation. These drawbacks substantially increase the fire danger to occupants, property, and emergency response personnel. Thus, self-contained smoke alarms have serious limitations relating to alerting building occupants, who are in turn responsible for contacting emergency response personnel.
In response to the above, some federal, state, and/or local fire codes may require that new residences incorporate multiple, self-contained smoke alarms equipped with hard-wired interconnection terminals forming a network and thus permitting the activation of multiple smoke alarms. The interconnection terminals allow multiple smoke alarms to be interconnected within a building, so when any one of the interconnected smoke alarm senses smoke, other interconnected alarm are activated. One example of a networked smoke alarm system is described in U.S. Pat. No. 6,362,743. The FIRST ALERT® SA4121 smoke alarm also provides interconnection terminals.
Another type of smoke alarm system utilizes wireless interconnections to permit communication between the smoke alarms. However, this system requires short-range transceivers to transmit the wireless signal to/from other smoke alarms. One wireless smoke alarm system that provides a multiple alert smoke alarm in which two or more smoke alarms containing wireless FM transmitters provide multiple alarm activation is described in U.S. Pat. No. 5,587,805. A similar system is described in U.S. Pat. No. 5,019,805, which describes a smoke alarm featuring an interconnection via an AC power line carrier signal and interconnection via wireless signals.
Although interconnected smoke alarms may alert building occupants to fires in remote or unoccupied areas, if the building is unoccupied or vacant, the fire will go undetected, which may allow the fire to spread. Neighbors or other observers would have to notice the burning building and contact the emergency response personnel.
Other types of hard-wired or wireless interconnected smoke alarm systems are typically integrated with residential or commercial building security systems, which are primarily designed for intrusion detection and home automation. For example, a smoke alarm system called the NAPCO® GEMINI® system provides a modular residential security system comprising a separate wall-mounted control panel, a keypad, a wireless receiver, various wireless security sensors, and a wireless smoke alarm. The GEMINI® system may also include a telephone auto-dialer connected to a “wireless” telephone, which is configured to automatically notify a commercial security monitoring service upon activation.
Integrated security systems that include smoke alarms can be cost prohibitive if the primary goal of the building owner is to monitor for fire. Also, integrated security systems require skilled technicians to install, test, and maintain the entire system. In addition to the system complexity, installation, and maintenance costs, the integrated security system may not include a smoke alarm in the basic system configuration. Further, the integrated security system often requires an additional telephone line, requires an off site commercial security monitoring service, and requires the payment of monthly service fees.
Another drawback of the aforementioned smoke alarm devices and systems is that they are not designed for installation in buildings that are under construction or otherwise unoccupied. Workers at a construction site and/or persons in the immediate vicinity are the primary means for noticing a potential fire. Because unoccupied buildings are typically vacant during off-work hours, a fire may cause increased damage to the building, increased damage to adjacent properties, and/or pose an increased danger to emergency response personnel.
Another drawback of some self-contained and interconnected smoke alarms is the lack of effective means for automatically notifying emergency response personnel of the specific location of the fire emergency. Direct contact with a public 911 dispatch center, often referred to as a Public Safety Answering Point (“PSAP”), can be a factor in the response time of the emergency response personnel.
For example, during a fire emergency, evacuating building occupants are faced with sudden conflicting decisions, which include immediately evacuating the burning building, helping others to evacuate safely, gathering valuable property, or calling 911 to report the fire and summon emergency response resources.
In most cases, building occupants calling 911 in a fire emergency will use a conventional wireless telephone or a mobile cellular telephone to call 911. In such a situation, the caller may be in a heightened state of anxiety and confusion, so locating a telephone, dialing the number, waiting for a call connection, and articulating the nature of the emergency to a 911 dispatcher can waste critical evacuation time. These complexities place children, the elderly, and the handicapped at high risk.
Therefore, a need exists to provide a smoke alarm that automatically notifies a 911 dispatch center and automatically provides a geographic location of the emergency.
Wireless Telecommunication Systems, Mobile Cellular Telephones, and Emergency 911 Systems.
The existence of wireless telecommunications network systems, often referred to as cellular networks, along with mobile cellular telephones, are well known.
Due to a dramatic increase in 911 calls originating from mobile cellular telephones, wireless E-911 needed to be modified to provide a callback number, fixed address and/or geographic location information of mobile cellular telephone. Although the majority of wireless telephones in the United States have wireless E-911 capabilities, mobile cellular telephones do not.
Recognizing the proliferation of cellular phones, the Federal Communications Commission (“FCC”) enacted a regulation requiring wireless telecommunications carriers to upgrade and modify their wireless network infrastructure and cellular phone capabilities. The resulting system is known as a wireless telecommunications location system (“WTLS”), which allows an emergency response authority to automatically determine the geographic location of a mobile cellular telephone, and possibly even track the movements of the cellular phone during an emergency call. Accordingly, a new wireless location concept, called wireless Enhanced 911 (“wireless E-911”) service is being deployed nationwide. In addition, dispatch centers may be equipped with a modified Geographic Information System (“GIS”) that displays city or county maps and other information, to automatically pinpoint the geographic location of the wireless 911 caller. The emergency personnel may then be dispatched to the location of the cellular phone. Wireless E-911 is designed to save lives by reducing the response time and increasing the accuracy of emergency response resources responding to emergency calls. One system that uses wireless E-911 capabilities is described in U.S. Pat. No. 6,317,604.
Numerous wireless E-911 location concepts exist in the prior art to achieve WTLS capabilities. The numerous concepts include measuring the time difference of arrival and angle of arrival of signals transmitted from mobile cellular telephones to base station antennas. These concepts generally require a plurality of base station antennas to “triangulate” the signal transmission to determine the geographic location. These concepts operate best when there is a high concentration of base station antenna sites. Otherwise, increasing wireless transceiver amplifier output, or other supplemental means may be needed. One type of a base station antenna system is described in U.S. Pat. No. 6,184,829. These wireless location concepts may be governed by the FCC wireless E-911 Phase II network-based regulatory mandate requiring a WTLS to locate a wireless E-911 caller within 100 meters for 67% of calls, and/or within 300 meters for 95% of the calls.
One approach to identifying the location of a cellular phone is by integrating a Global Positioning System (“GPS”) receiver into the cellular phone. GPS is a popular satellite-based navigation system that provides coded satellite signals that are processed in a GPS receiver to yield the position and velocity of the receiver. This location method generally requires a line-of-sight signal transmission of a plurality of GPS satellites to determine the coordinates of the GPS receiver. A cellular phone that incorporates a GPS receiver is described in U.S. Pat. No. 6,353,412. According to an FCC regulation, a cellular phone with an integrated GPS receiver must provide a location accuracy within 50 meters for 67% of the calls, and/or within 150 meters for 95% of the calls.
Hybrid wireless locations concepts that combine the above-stated network and handset-based locations concepts exist to reduce the number of base station antenna sites and GPS satellites needed to locate a mobile cellular telephone. These hybrid location concepts may utilize augmented GPS (e.g., assisted GPS, differential GPS), or synchronize the GPS satellites and WTLS base station sites, offering a faster location process. A similar wireless location concept is described in U.S. Pat. No. 6,323,803. Hybrid location concepts may exceed FCC wireless E-911 regulatory mandates by increasing location accuracy and reducing location determination time.
Certain basic technical aspects have an essential role in WTLS. Generally, air interface protocols (e.g., TDMA, CDMA, GSM, GPRS, AMPS, N-AMPS) and relative frequencies operate in conjunction with a wireless telecommunications transceiver (hereinafter referred to as a “wireless transceiver”)—an essential component of a mobile cellular telephone—to transmit signals over the WTLS for location determination. All air interface protocols primarily utilize two types of “channels” for wireless signal transmission.
The first type is a control channel, which is typically used for transmitting general identifying information pertaining to the wireless transceiver transmitting the signal. The second type is a voice channel, used primarily for voice communications. Because a voice channel typically does not provide identification information of the wireless transceiver, control channels are often used for wireless location purposes.
In addition, the latest technology allows a wireless transceiver to contain a fully integrated “system on a chip.” In one embodiment, the wireless transceiver is of a dual-band and/or dual-mode configuration (e.g., GSM/GPRS) to optimize voice communications, text messaging (i.e., Short Message Service (“SMS”)), and Multi-Media Service (“MMS”), and contain on-chip memory capabilities. Further, Personal Digital Assistants (“PDA's”) include wireless transceivers. PDA's may also integrate wireless local-area network (“W-LAN”) modules for wireless data communications with other PDA's or personal computers.
Additional FCC regulations include providing wireless “priority access” service to federal, state, and local public safety and emergency response personnel utilizing mobile cellular telephones. Wireless priority access service provides public safety authorities priority access on wireless telecommunications network systems during widespread emergencies, when the number of calls exceeds the system call capacity. Priority access service could also provide benefits for wireless E-911 location services.
One drawback of the aforementioned wireless location concept is that it is primarily designed for determining the geographic location of voice-only mobile cellular telephones. The intended use of wireless E-911 location requires the caller to manually enter the “9-1-1” numeric sequence or some variation into the cellular handset keypad. Once a connection is made, the user must then verbally articulate the nature of the emergency to a 911 dispatch center. Although mobile cellular telephones are an important tool for general safety and emergency reporting, they still require a human user to operate, and are not specially designed for fire safety.
Another drawback is that in order to utilize wireless E-911 emergency location services, a user must first purchase or acquire a non-operational mobile cellular telephone, and then enter into a service contract with a wireless telecommunications carrier, which requires an activation fee and monthly service fee. To help alleviate this problem, the FCC issued an order entitled, “Enhanced 911 Emergency Calling Use of Non-initialized Wireless Phones,” which provides for “911 only” mobile cellular telephones to have basic wireless E-911 functionality without requiring the cellular owner to enter into a service contract with a wireless carrier, pay an activation fee, and pay monthly service fees. However, these mobile cellular telephones are not specialized for fire safety.
As described above, presently available conventional smoke alarms are primarily used for alerting building occupants with an audible or visual alarm, but do not provide a means to automatically and directly contact a 911 dispatch center. Therefore, in light of the foregoing disadvantages inherent in prior art smoke alarms, a need exists for a new and improved combination smoke detection device that automatically detects fire emergencies, automatically determines the geographic location of the fire emergency, and automatically contacts an emergency dispatch center to warn of a fire emergency situation.